This invention relates generally to medical diagnosis, and more particularly to the automated diagnosis of medical conditions from images of a patient.
One type of medical condition or disease that is of interest to the medical community are neurodegenerative disorders (NDDs). However, NDDs may be challenging to treat and/or study because they are both difficult to detect at an early stage and hard to quantify in a standardized manner for comparison across different patient populations. In response to these difficulties, investigators have developed methods to determine statistical deviations from normal patient populations.
These earlier methods include transforming patient images using two types of standardizations, anatomical and intensity. Anatomical standardization transforms the images from the patient's coordinate system to a standardized reference coordinate system. Intensity standardization involves adjusting the patient's images to have equivalent intensity to reference images. The resulting transformed images may then be compared to a reference database. The database includes age and tracer specific reference data. Most of the resulting analysis takes the form of point-wise or region-wise statistical deviations, typically depicted as Z scores. In some embodiments, the tracer is a radioactive tracer used in nuclear imaging.
One element of the detection of NDD is the development of age and tracer segregated normal databases. Comparison to these normals can only happen in a standardized domain, e.g. the Talairach domain or the Montreal Neurological Institute (MNI) domain. The MNI defines a standard brain by using a large series of magnetic resonance imaging (MRI) scans on normal controls. The Talairach domain is references a brain that is dissected and photographed for the Talairach and Tournoux atlas. In both the Talairach domain and the MNI domain, data must be mapped to the respective standard domain using registration techniques. Current methods that use a variation of the above method include tracers NeuroQ®, Statistical Parametric matching (SPM), 3D-sterotactic surface projections (3D-SSP), and so forth.
Once a comparison has been made, an image representing a statistical deviation of the anatomy is displayed, allowing a viewer to make a diagnosis based on the image. Making such a diagnosis is a very specialized task and is typically performed by highly trained medical image experts. However, even such experts can only make a subjective call as to the degree of severity of the disease. Due to this inherent subjectivity, the diagnoses tend to be inconsistent and non-standardized. It may, therefore, be desirable to increase the consistency and standardization of such diagnoses.